Leak detector



Sept. 14, 1948.

.H. I... BURNS ETAL LEAK DETECTOR Filed Nov. 28; 1944' 5 3 MZW Ty N m mam w L. s f. 5 y ad I.. w 0 22m 2 an m 2 M C "I. 2 '6 u m m a a -4 w 4L a w l H a m Patented Sept. 14, 1948 LEAK DETECTOR Henry L. Burns,'Yellow Springs, Ohio, and James H. Thomas, Minneapolis, Minn.

Application November 28, 1944, Serial No. 565,560

(Granted under the act of March a, 1883, as amended April 30, 1928; 370 0. G. 757) 4 Claims.

The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to us of any royalty thereon.

This invention relates to leak detectors and more particularly to a leak detector adapted to detect leaks in oxygen demand masks or the like.

One object of the present invention is to pro: vide a leak detector which will be easy to apply and use.

Another object of the invention is to provide a leak detector which will be light and easily portable.

A further object is to provide a leak detector which is simple and economical to manufacture.

Other objects will become apparent from the accompanying drawings, which, when taken in connection with the present specificationadisclose a preferred form of the invention.

In terms of broad inclusion, the invention comprises a bellows having an opening in one end thereof to receive the supply end of a supply pipefrom a demand type oxygen mask, and a weight on the opposite end of the bellows to expand the bellows to indicate leaks in the mask.

In the drawings:

Fig. 1 is a perspective view of a leak detector embodying the present invention, the leak detector being shown connected to a demand type oxygen mask; and

Fig. 2 is a vertical cross-sectional View of the leak detector shown in Fig. l, but with the bellows extended.

Referring particularly to the drawings, the leak detector comprises a flexible bellows I formed of rubber or similar material and secured at its upper end between a casing I2 and a cap I3. Casing I2 is the upper shell of a bellows-housing assembly and is formed as illustrated with a rab-. beted edge 12a in its side wall and a central opening I2b in its top wall. A bead II is provided at the top edge of easing I2 to facilitate holding of the detector by the user. The bellows I0 is flanged at its top and bottom ends, as shown at Illa and lb in Figure 2, and the casing I2 and cap I3 form a closure assembly for the top flanged end of the bellows which extends through and has a snug lit in the central opening I2b of the casing. A circular recess I and a circular V-groove or notch I 2d are provided in the outer face of easing I2 concentric with the central opening I2b. Recess I20 extends around the top edge of the opening I 21) and provides a seat for the top flange Illa of the bellows. The V-notch I2d is spaced outwardly of the flange seat I20 and aids in centering the cap I3 on the top face of the casing and over the opening I21) during assembly of the parts so as to substantially close the bellows at its upper end; the portion of the cap opposite the V-groove I2d of= the casing being provided with an inwardly projecting circular V-rib I3a fitting the V-notch I2d. In addition to the V-rib I3a, the cap I3 is provided with an inwardly projecting circular flange or ring I3b having a snug fit in the upper end of the bellows and serving, together with the portion of the cap opposite the seated bellows flange IIIa, to clamp the top end ofxthe bellows between the casing I2 andthe cap I3,

The cap I3 has a central aperture I4 therein which is in communication with the interior of the bellows and which is of a suitable size and shape to receive a mask connector such as the coupling I5 on the inlet hose I! of a demand type oxygen mask I9 The aperture I I has a shoulder I8 which is engaged by a bead IE on the coupling I5 to secure the coupling in the aperture.

,Cover I9 is the lower shell of the bellows-housing assembly and together with the cap or closure plate 20, forms a closure assembly for the bottom flanged end of the bellows which extends through and has a snug fit in a central opening I9b in the cover. A circular recess I and a circular V-groove or notch I9d are provided in the outer face of the cover concentric with the central opening I9b. Recess I90 extends around the bottom edge of the opening I9b and provides a seat for the bottom flange III!) of the bellows. The V-notch I9d is spaced outwardly of the flange seat I9 c and aids in centering the plate on the bottom face of the cover and over the opening I91) during assembly of the parts so as to close the bellows at its bottom end; the plate 20 being imperforate and having the portion thereof opposite the V-notch I9d provided with an inwardly projecting circular V-rib 20a fiting the V-notch I 9d. In addition to the V-rib 20a, the plate 20 is provided with an inwardly projecting circular flange or ring 20b having a snug fit in the lower end of the bellows and serving, together with the portion of the plate opposite the seated bellowsflange I01), to clamp the bottom end of the bellows between the casing cover I9 and the closure plate 20.

After the bellows III has been assembled between the housing members I2 and I3 at one end and between the housing members I9 and 20 at the other end, the said members are cemented together at the V-notches lid anaos and I9d to make a leaktight mechanical seal with the bellows. Since the bellows is attached and sealed to the housing by being clamped between the housing members at each end, a tight sealing of the ends of the bellows to the end housing members isobtained without cementing the ends of the bellows to the housing members. Hence; when the tester is connected with the mask, the bellows is a leaktight enclosure into and out of which no air can flow except through the mask connector I5, The bottom cover l9 has an upturned flange 22 around the edge thereof which; in the collapsed condition of the bellows, engages with the rabbeted edge I2a of the casing I2 to form a closed container housing the bellows when the device is not in use.

The casing l2, cap l3, bottom cover l9, and plate 20 are preferably formed plastic to pro; vide a cylindrical light weight instrument and the cover l9 and plate 20 are of such combined weight to expand the bellows and produce a predetermined suction on the interior of the bel-' lows.

Operation In operation, the mask to be tested is worn onthe face of the user who holds the detector a closed horizontal position and plugs it into his mask through the coupling 15 while holding his breath, thus forming a completely closed system. When the bottom cover I9 is released, if there is no leak in the system, the air pressure will hold the bottom cover up in partially extended" position. However, if the mas'k'is leaking for any reason, the bellows lll will expand, and the bottom cover l9 will drop accordingly. The speed with which the bottom cover [9 dropsis dependent upon the amount of air leaking into 'tlie' nia'sk'.

Thus if thefit of the mask issuch as tdallovf inflow of external gas, the bottom cover t9 will descend until the detector has reached an efi tended position as shown in Fig. 2 If the mask fits well, the bottom cover IQi-willeither remain in a raised position, or will descends'o slowly as to indicate that the leak is of such small" magnitude as to be considered negligible;

After testing the mask' for leaks the leak? de tector is disconnected from" the mask"- and the coupling [5 plugged into the o'iiyg'e'n supply;

It is realized that the described embodiment of the invention is susceptible to various changes andmodifications and that such clirriges'inshape;- size" and arrangement ofp'a'rt's may be" made as fall within the scope of the appended 1aims.-

That which is claimed as new and is desired to be-secured by'Letters Patent is: I

1. A leak detector for a'demandaypemask pro vided with an'inl'et hose anda maie'nose-ceuplmg on said hose, said detector comprising a casing having an opening in' the top thereof, a cap cov ering the said opening andh'av-in'g a female fitting thereon adapted to receive the said maleh'o'se coupling; a bottom cover forthesaid'casingha ing an opening in the botto'ni thereof closure plate covering the said opening in; the cover; a bellows having its opposite" ends disposed in tlie openings respectively of the casing a'n'd the coverand engaged between the casing and the capat one end and between the cover and the closure plate at the other end, the f'emale' fitting 'dn tifc'ap opening into the said bellows-'arid the"said cap and closure plate'beih'g securedto' the ca'sing arid cover respectively to clamp theehdmof the b'el lowstherebetween and; provide a lealtight en'clo sure except for the opening in the female fitting, and means to secure the male hose-coupling in the said opening in the female fitting so that the hose connects with the interior of the bellows and provides the only inlet and outlet for the flow of air into and out of the, said bellowsa "2. A Ieal tester'ror a deinind'type'okygn mask provided with an inlet hose and a connector on the said hose, said tester comprising a cylindrical casing open at its bottom and having an opening in its top wall, a cap on the top wall of the casing and extending over the said opening, said cap being secured to the casing and having an aperture adapted to receive the said connector, a cylindrical cover for the bottom of the casing having an opening in its bottom wall, a closure plate on the bottom wall of the cover and extending over the said opening in the cover, said closure plate being secured to the cover and being imperiorate, and a bellows between the casing and the cover and extending through the said openings in each witl'iits' upper" end clamped between the casing and, the cap and its lower end clamped between the cover and the closure plate to pro vide a le'aktight enclosure whereby when the bellows is attached to the mask to be testedn'o air can pass into or out of the bellows except through the mask connector, the said cover' and closure plate being of such combined weight to expand the bellows and produce a predetermined suction on the interior of the bellows during the testing operation.

3. A leak tester for a demand type oxygen maskprovided with an inlet hose and a connector on the said l'lose, Said tester comprisin a flexible bellows flanged at its top and bottom ends and a closure assembly at each end of the bellows, each closure assembly comprising ahous'ing 11bit and a cap between which an end of thebellows'is'secuieit' the' saidhousingunit' having" an opening in which the e'nd of the bellows has a snug fit and" having in its outer face a recess around the outer" edge" or the" o enin to seat the flange of the bellows and a-V-n'otch extending'lar oun'd th'e'seatin' outwater spaced relation thereto, the said" caste: ing on the outer face of the housing" u'r'iit alridxtending over the said opening aridthe recess and the V-n'otch in the unit and" liaviri'g an army pro ecting rib fitting the said V-riot'chaii' having an inwardly projecting flange fitting snugly in the end' of the bellows and serving together with that portion of the cap outsidethe seated'be'llow'sflange to clamp the bellows between the cap" and the housing'unit, said cap ananou'smg' uhit-belng cemented together at the v'-r1otc1i-;- the cap of one of the assemblies having an opening adapted to receive and be pluggedby'th'e said connector:

4. Aleak tSter for a demandtvpe oxygen'man cdn'iprisihg a flexible bellows and a closure as: se'ihbly at each end of the; bellows" andjcoris'ist ii'fg of'a pair or sliperposed sealing members an: gtg'iiig the end of the bellows awn inner: and outer' surfaces thereof, onernember' of each as sembly having a c'entralopenii'ig'iii Whichhririd' of thbellows is received and being a"casing'ha';v ing matingcontact with the (firrspC3i'-i"c1 ii'ig m'e befof the other assembiyto-neuseth bell therebetw'eh' and the other member ofcab aS'- snibl-ybein'g' on the exterior side of its' associate casingmember and covering th" (fei ii'lil'all op'fi' ingin thesald casingnie'rhbf to preview-cap or closurefor' tlidehd-o'f the bellows said c and cap havihg"intere1' igaged porti-ons form wiigue-ahd-grobve joint? on theeitt'eri assembly and outwardly of and around the" 5 6 clamped end of the bellows, said members being REFERENCES CITED cemented together at the omt and clamping the I engaged end of t bellows therebetween t The following references are of record 1n the vide a leaktight seal between the bellows and the file 0f thls Patent: closure assembly, one of said assemblies having 5 UNITED STATES PATENTS a female fitting for receiving a male coupling such as the conventional mask connector attached to Number Name Date the inlet hose of the mask to 'be tested and the 1,933,322 Oct 31, 1933 other assembly being. of a. weight to provide a 21420372 Heldbrmk MW 13, 1947 predetermined suction on the interior of the bell0 FOREIGN PATENTS lows when released to expand the bellows.

Number Country Date Germany 

